Early motion processes and the kinetic depth effect

It has been known for over 30 years that motion information alone is sufficient to yield a vivid impression of three-dimensional object structure. For example, a computer simulation of a transparent sphere, the surface of which is randomly speckled with dots, gives no impression of depth when presented as a stationary pattern on a visual display. As soon as the sphere is made to rotate in a series of discrete steps or frames, its 3-D structure becomes apparent. Three experiments are described which use this stimulus, and find that depth perception in these conditions depends crucially on the spatial and temporal properties of the display:

1. Depth is seen reliably only for between-frame rotations of less than 15°, using two-frame and four-frame sequences.

2. Parametric observations using a wide range of frame durations and inter-frame intervals reveal that depth is seen only for inter-frame intervals below 80 msec and is optimal when the stimulus can be sampled at intervals of about 40-60 msec.

3. Monoptic presentation of two frames of the stimulus is sufficient to yield depth, but the impression is destroyed by dichoptic presentation.

These data are in close agreement with the observed limits of direction perception in experiments using “short-range” stimuli. It is concluded that depth perception in the motion display used in these experiments depends on the outputs of low-level or “short-range” motion detectors.     

Book reviews

Weiskrantz, L. (1986). Blindsight: A case study and implications. Oxford University Press. Pp. 187. ISBN 0-19-852129-4. £19.50.

Humphreys, G. W. & Riddoch, M. J. (1987). to see but not to see: A case study of visual agnosia. Hove and London: Lawrence Erlbaum Associates Ltd. Pp. 124. ISBN 0-83677-064-9. £12.95.

Downing, J. A. (1988). Advances in psychology: Cognitive psychology and reading in the USSR. Amsterdam: North Holland; Elsevier Science Publishers. Pp. 471. ISBN 0-444-70374-8. $108.00.

John Beech & Ann Colley (Eds.) (1987). Cognitive approaches to reading. Chichester: John Wiley. Pp. xii + 315.

James Wertsch (Ed.) (1985). Culture, communication and cognition: Vygotskian perspectives. Cambridge: Cambridge University Press. Pp. 379. ISBN 0-521-25214-8. £27.50 (Hardback).

Fodor, J. A. (1987). Psychosemantics: The problem of meaning in the philosophy of mind. Cambridge, MA: M.I.T. Press. Pp. xiii, 1-171. ISBN 0-262-06106-6.

Richardson, K. (1988). Understanding Psychology. Milton Keynes: The Open University Press. Pp. 114. ISBN 0-335-09842-8. Paperback £7.95.

Stanovich, Keith E. (Ed.) (1988). Children's reading and the development of phonological awareness. Detroit: Wayne State University Press. Pp. 177. ISBN 0-8143-1909-2. $20.00.

Allport, A., MacKay, D.G., Prinz, W., & Scheerer, E. (Eds.), (1987). Language perception and production: Relationships between listening, speaking, reading, and writing. London: Academic Press. Pp. xiii + 497. ISBN 0-12-052750-2. £32.00

Light, L. L. & Burke, D. M. (eds.) (1988). Language, Memory and Aging. Cambridge: Cambridge University Press. Pp. 280. ISBN-0-521-32942-6. £27.50

Friedman, S.L., Scholnick, E.F., and Cocking, R. R. (1987). Bleuprints for thinking: The role of planing in cognitive development. Cambridge: Cambridge University Press. Pp. xv + 559. ISBN 0-521-25605-4. £40.00.     

DETERMINANTS AND CONSEQUENCES OF CREATIVITY IN A COHORT OF GIFTED WOMEN

Forty women who had been selected by Lewis Terman in 1921 for his study of intellectually gifted California school children were reinterviewed in 1987 (Mean = 77 years, SE±1). These women had been prospectively followed by questionnaire over the intervening 65 years. Their capacity for creativity–putting something in the world that was not there before–was assessed by review of their prospectively gathered questionnaires and by retrospective interview. The 20 women viewed as most creative (usually for literary publication, art, music, or starting an organization) were more likely in the past to have manifested generativity, and at the present to have adjusted well to old age. Although the ego defenses of sublimation, humor, and altruism were more frequent among the creative women, no differences were noted in the happiness of their childhoods or their mental health prior to the present.